-2
votes
2answers
28 views

Explicit transactions for each DML query are necessary or not? [on hold]

My question is simple: Which mechanism should I use in databases to ensure that if device shuts down in middle, the process is unified. transactions?
0
votes
1answer
59 views

What's faster: two UPDATEs with WHERE (in / not in) or one UPDATE with CASE?

What's best performance wise, two separate UPDATEs: UPDATE table1 SET enabled = 0 WHERE code NOT IN ( SELECT id FROM table2 ); UPDATE table1 SET enabled = 1 WHERE ...
0
votes
1answer
49 views

Audit DML operations on MySQL Tables

We have several MySQL 5.0 databases. We've been having security problems, like records being modified without authorization. We need to implement some kind of audit on DML operations identifying ...
7
votes
1answer
4k views

Why would an UPDATE SET REPLACE() statement match rows, but change none and give no warnings?

I'm seeking a certain string in a field and want to replace it with a new string. Specifically, I want all references to one URL to be changed to another URL. I've crafted this SQL statement and am ...
2
votes
1answer
275 views

MySQL Update: why would rows matched change based on the set clause?

I ran an update query joining across a huge number of tables that updated one field, and it matched 29k some-odd rows. Running the same query with only an addition in the Set clause increased the ...